Hitherto, there is an air-conditioning apparatus which makes an evaporating temperature and a condensing temperature, which are control target temperatures in a refrigeration cycle, variable in accordance with a load (see Patent Literature 1). The air-conditioning apparatus performs an operation with a low compression ratio at the time of low load by making an evaporating temperature and a condensing temperature, which are control target temperatures, to be variable values in accordance with an air-conditioning load estimated based on an operation mode and the difference between a set temperature and a suction temperature, thereby reducing power consumption.
In addition, because of a multi-type, a plurality of indoor units operate under respective load conditions at the same time, and the method is a method in which a condensing temperature and an evaporating temperature of refrigerant are controlled to constant values, not a method in which a blowout temperature of refrigerant is controlled for individual indoor units.
In this method, the difference between the suction temperature and the set temperature is monitored. When “suction temperature−set temperature” becomes equal to or less than a predetermined value, it is determined that the air-conditioning load is low. If the operation is a cooling operation, by increasing the evaporating temperature which is a control target, it is possible to decrease the frequency of a compressor to reduce power consumption. In addition, if the operation is a heating operation, by decreasing the condensing temperature which is a control target, it is possible to decrease the frequency to reduce power consumption.